The Collaborative International Dictionary of English v.0.48:

Repeater \Re*peat"er\ (-?r), n.
   One who, or that which, repeats. Specifically:
   (a) A watch with a striking apparatus which, upon pressure of
       a spring, will indicate the time, usually in hours and
       quarters.
   (b) A repeating firearm.
   (c) (Teleg.) An instrument for resending a telegraphic
       message automatically at an intermediate point.
   (d) A person who votes more than once at an election. [U.S.]
   (e) See Circulating decimal, under Decimal.
   (f) (Naut.) A pennant used to indicate that a certain flag in
       a hoist of signal is duplicated. --Ham. Nav. Encyc.
       [1913 Webster]

WordNet (r) 3.0 (2006):

repeater
    n 1: a person who repeats; "the audience consisted largely of
         repeaters who had seen the movie many times"
    2: someone who is repeatedly arrested for criminal behavior
       (especially for the same criminal behavior) [syn:
       recidivist, repeater, habitual criminal]
    3: a firearm that can fire several rounds without reloading
       [syn: repeating firearm, repeater]
    4: (electronics) electronic device that amplifies a signal
       before transmitting it again; "repeaters can be used in
       computer networks to extend cabling distances"

Moby Thesaurus II by Grady Ward, 1.0:

37 Moby Thesaurus words for "repeater":
   automatic, backslider, ballot-box stuffer, balloter, blowgun,
   blowpipe, elector, firearm, flamethrower, floater,
   fraudulent voter, gat, gun, handgun, heater, lost lamb, musket,
   peashooter, piece, pistol, prodigal son, proxy, recidivist,
   registered voter, returnee, reversioner, reversionist, revolver,
   rifle, rod, sawed-off shotgun, shooting iron, shotgun, six-gun,
   six-shooter, two-time loser, voter



The Free On-line Dictionary of Computing (30 December 2018):

repeater

    A network or communications
   device which propagates electrical signals from one cable to
   another, amplifying them to restore them to full strength in
   the process.  Repeaters are used to counter the attenuation
   which occurs when signals travel long distances (e.g. across
   an ocean).

   A network repeater is less intelligent than a bridge,
   gateway or router since it works at the physical layer.

   (1998-07-16)